On Thu, 2012-11-15 at 20:13 +0000, Nicholas A. Bellinger wrote:
> From: Nicholas Bellinger <nab@xxxxxxxxxxxxxxx>
>
> This patch adds a new max_write_same_len device attribute for use with
> WRITE_SAME w/ UNMAP=0 backend emulation. This can be useful for
> lowering the default backend value (IBLOCK uses 0xFFFF).
>
> Also, update block limits VPD emulation code in spc_emulate_evpd_b0() to
> report MAXIMUM WRITE SAME LENGTH, and enforce max_write_same_len during
> sbc_parse() -> sbc_setup_write_same() CDB sanity checking for all emulated
> WRITE_SAME w/ UNMAP=0 cases.
>
> Cc: Christoph Hellwig <hch@xxxxxx>
> Cc: Martin K. Petersen <martin.petersen@xxxxxxxxxx>
> Signed-off-by: Nicholas Bellinger <nab@xxxxxxxxxxxxxxx>
> ---
> drivers/target/target_core_configfs.c | 4 ++++
> drivers/target/target_core_device.c | 11 +++++++++++
> drivers/target/target_core_internal.h | 1 +
> drivers/target/target_core_sbc.c | 8 ++++++++
> drivers/target/target_core_spc.c | 8 +++++++-
> include/target/target_core_base.h | 3 +++
> 6 files changed, 34 insertions(+), 1 deletions(-)
>
<SNIP>
> diff --git a/drivers/target/target_core_sbc.c b/drivers/target/target_core_sbc.c
> index a5a8f46..8dd8a802 100644
> --- a/drivers/target/target_core_sbc.c
> +++ b/drivers/target/target_core_sbc.c
> @@ -238,6 +238,8 @@ static inline unsigned long long transport_lba_64_ext(unsigned char *cdb)
> static sense_reason_t
> sbc_setup_write_same(struct se_cmd *cmd, unsigned char *flags, struct sbc_ops *ops)
> {
> + unsigned int sectors = spc_get_write_same_sectors(cmd);
> +
> if ((flags[0] & 0x04) || (flags[0] & 0x02)) {
> pr_err("WRITE_SAME PBDATA and LBDATA"
> " bits not supported for Block Discard"
> @@ -258,6 +260,12 @@ sbc_setup_write_same(struct se_cmd *cmd, unsigned char *flags, struct sbc_ops *o
> if (!ops->execute_write_same)
> return TCM_UNSUPPORTED_SCSI_OPCODE;
>
> + if (sectors > cmd->se_dev->dev_attrib.max_write_same_len) {
> + pr_warn("WRITE_SAME sectors: %u exceeds max_write_same_len: %u\n",
> + sectors, cmd->se_dev->dev_attrib.max_write_same_len);
> + return TCM_INVALID_CDB_FIELD;
> + }
> +
> cmd->execute_cmd = ops->execute_write_same;
> return 0;
> }
Now moving the max_write_same_len check above directly ahead of the
UNMAP conditional branch, so that both WRITE_SAME w/ UNMAP=[1,0] are
properly checked against this value as per hch's + Robert's input.
Thanks!
--nab
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